Add m-esr52 at 52.6.0

1 files changed, 1147 insertions, 0 deletions

diff --git a/addon-sdk/source/lib/toolkit/loader.js b/addon-sdk/source/lib/toolkit/loader.js
new file mode 100644
index 000000000..4c22550d8
--- /dev/null
+++ b/addon-sdk/source/lib/toolkit/loader.js
@@ -0,0 +1,1147 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+;((factory) => { // Module boilerplate :(
+  if (typeof(require) === 'function') { // CommonJS
+    require("chrome").Cu.import(module.uri, exports);
+  }
+  else if (~String(this).indexOf('BackstagePass')) { // JSM
+    let module = { uri: __URI__, id: "toolkit/loader", exports: Object.create(null) }
+    factory(module);
+    Object.assign(this, module.exports);
+    this.EXPORTED_SYMBOLS = Object.getOwnPropertyNames(module.exports);
+  }
+  else {
+    throw Error("Loading environment is not supported");
+  }
+})(module => {
+
+'use strict';
+
+module.metadata = {
+  "stability": "unstable"
+};
+
+const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu,
+        results: Cr, manager: Cm } = Components;
+const systemPrincipal = CC('@mozilla.org/systemprincipal;1', 'nsIPrincipal')();
+const { loadSubScript } = Cc['@mozilla.org/moz/jssubscript-loader;1'].
+                     getService(Ci.mozIJSSubScriptLoader);
+const { addObserver, notifyObservers } = Cc['@mozilla.org/observer-service;1'].
+                        getService(Ci.nsIObserverService);
+const { XPCOMUtils } = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
+const { NetUtil } = Cu.import("resource://gre/modules/NetUtil.jsm", {});
+const { join: pathJoin, normalize, dirname } = Cu.import("resource://gre/modules/osfile/ospath_unix.jsm");
+
+XPCOMUtils.defineLazyServiceGetter(this, "resProto",
+                                   "@mozilla.org/network/protocol;1?name=resource",
+                                   "nsIResProtocolHandler");
+XPCOMUtils.defineLazyServiceGetter(this, "zipCache",
+                                   "@mozilla.org/libjar/zip-reader-cache;1",
+                                   "nsIZipReaderCache");
+
+XPCOMUtils.defineLazyGetter(this, "XulApp", () => {
+  let xulappURI = module.uri.replace("toolkit/loader.js",
+                                     "sdk/system/xul-app.jsm");
+  return Cu.import(xulappURI, {});
+});
+
+// Define some shortcuts.
+const bind = Function.call.bind(Function.bind);
+const getOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;
+const prototypeOf = Object.getPrototypeOf;
+const getOwnIdentifiers = x => [...Object.getOwnPropertyNames(x),
+                                ...Object.getOwnPropertySymbols(x)];
+
+const NODE_MODULES = new Set([
+  "assert",
+  "buffer_ieee754",
+  "buffer",
+  "child_process",
+  "cluster",
+  "console",
+  "constants",
+  "crypto",
+  "_debugger",
+  "dgram",
+  "dns",
+  "domain",
+  "events",
+  "freelist",
+  "fs",
+  "http",
+  "https",
+  "_linklist",
+  "module",
+  "net",
+  "os",
+  "path",
+  "punycode",
+  "querystring",
+  "readline",
+  "repl",
+  "stream",
+  "string_decoder",
+  "sys",
+  "timers",
+  "tls",
+  "tty",
+  "url",
+  "util",
+  "vm",
+  "zlib",
+]);
+
+const COMPONENT_ERROR = '`Components` is not available in this context.\n' +
+  'Functionality provided by Components may be available in an SDK\n' +
+  'module: https://developer.mozilla.org/en-US/Add-ons/SDK \n\n' +
+  'However, if you still need to import Components, you may use the\n' +
+  '`chrome` module\'s properties for shortcuts to Component properties:\n\n' +
+  'Shortcuts: \n' +
+  '    Cc = Components' + '.classes \n' +
+  '    Ci = Components' + '.interfaces \n' +
+  '    Cu = Components' + '.utils \n' +
+  '    CC = Components' + '.Constructor \n' +
+  'Example: \n' +
+  '    let { Cc, Ci } = require(\'chrome\');\n';
+
+// Workaround for bug 674195. Freezing objects from other compartments fail,
+// so we use `Object.freeze` from the same component instead.
+function freeze(object) {
+  if (prototypeOf(object) === null) {
+      Object.freeze(object);
+  }
+  else {
+    prototypeOf(prototypeOf(object.isPrototypeOf)).
+      constructor. // `Object` from the owner compartment.
+      freeze(object);
+  }
+  return object;
+}
+
+// Returns map of given `object`-s own property descriptors.
+const descriptor = iced(function descriptor(object) {
+  let value = {};
+  getOwnIdentifiers(object).forEach(function(name) {
+    value[name] = getOwnPropertyDescriptor(object, name)
+  });
+  return value;
+});
+Loader.descriptor = descriptor;
+
+// Freeze important built-ins so they can't be used by untrusted code as a
+// message passing channel.
+freeze(Object);
+freeze(Object.prototype);
+freeze(Function);
+freeze(Function.prototype);
+freeze(Array);
+freeze(Array.prototype);
+freeze(String);
+freeze(String.prototype);
+
+// This function takes `f` function sets it's `prototype` to undefined and
+// freezes it. We need to do this kind of deep freeze with all the exposed
+// functions so that untrusted code won't be able to use them a message
+// passing channel.
+function iced(f) {
+  if (!Object.isFrozen(f)) {
+    f.prototype = undefined;
+  }
+  return freeze(f);
+}
+
+// Defines own properties of given `properties` object on the given
+// target object overriding any existing property with a conflicting name.
+// Returns `target` object. Note we only export this function because it's
+// useful during loader bootstrap when other util modules can't be used &
+// thats only case where this export should be used.
+const override = iced(function override(target, source) {
+  let properties = descriptor(target)
+  let extension = descriptor(source || {})
+  getOwnIdentifiers(extension).forEach(function(name) {
+    properties[name] = extension[name];
+  });
+  return Object.defineProperties({}, properties);
+});
+Loader.override = override;
+
+function sourceURI(uri) { return String(uri).split(" -> ").pop(); }
+Loader.sourceURI = iced(sourceURI);
+
+function isntLoaderFrame(frame) { return frame.fileName !== module.uri }
+
+function parseURI(uri) { return String(uri).split(" -> ").pop(); }
+Loader.parseURI = parseURI;
+
+function parseStack(stack) {
+  let lines = String(stack).split("\n");
+  return lines.reduce(function(frames, line) {
+    if (line) {
+      let atIndex = line.indexOf("@");
+      let columnIndex = line.lastIndexOf(":");
+      let lineIndex = line.lastIndexOf(":", columnIndex - 1);
+      let fileName = parseURI(line.slice(atIndex + 1, lineIndex));
+      let lineNumber = parseInt(line.slice(lineIndex + 1, columnIndex));
+      let columnNumber = parseInt(line.slice(columnIndex + 1));
+      let name = line.slice(0, atIndex).split("(").shift();
+      frames.unshift({
+        fileName: fileName,
+        name: name,
+        lineNumber: lineNumber,
+        columnNumber: columnNumber
+      });
+    }
+    return frames;
+  }, []);
+}
+Loader.parseStack = parseStack;
+
+function serializeStack(frames) {
+  return frames.reduce(function(stack, frame) {
+    return frame.name + "@" +
+           frame.fileName + ":" +
+           frame.lineNumber + ":" +
+           frame.columnNumber + "\n" +
+           stack;
+  }, "");
+}
+Loader.serializeStack = serializeStack;
+
+class DefaultMap extends Map {
+  constructor(createItem, items = undefined) {
+    super(items);
+
+    this.createItem = createItem;
+  }
+
+  get(key) {
+    if (!this.has(key)) {
+      this.set(key, this.createItem(key));
+    }
+
+    return super.get(key);
+  }
+}
+
+const urlCache = {
+  /**
+   * Returns a list of fully-qualified URLs for entries within the zip
+   * file at the given URI which are either directories or files with a
+   * .js or .json extension.
+   *
+   * @param {nsIJARURI} uri
+   * @param {string} baseURL
+   *        The original base URL, prior to resolution.
+   *
+   * @returns {Set<string>}
+   */
+  getZipFileContents(uri, baseURL) {
+    // Make sure the path has a trailing slash, and strip off the leading
+    // slash, so that we can easily check whether it is a path prefix.
+    let basePath = addTrailingSlash(uri.JAREntry).slice(1);
+    let file = uri.JARFile.QueryInterface(Ci.nsIFileURL).file;
+
+    let enumerator = zipCache.getZip(file).findEntries("(*.js|*.json|*/)");
+
+    let results = new Set();
+    for (let entry of XPCOMUtils.IterStringEnumerator(enumerator)) {
+      if (entry.startsWith(basePath)) {
+        let path = entry.slice(basePath.length);
+
+        results.add(baseURL + path);
+      }
+    }
+
+    return results;
+  },
+
+  zipContentsCache: new DefaultMap(baseURL => {
+    let uri = NetUtil.newURI(baseURL);
+
+    if (baseURL.startsWith("resource:")) {
+      uri = NetUtil.newURI(resProto.resolveURI(uri));
+    }
+
+    if (uri instanceof Ci.nsIJARURI) {
+      return urlCache.getZipFileContents(uri, baseURL);
+    }
+
+    return null;
+  }),
+
+  filesCache: new DefaultMap(url => {
+    try {
+      let uri = NetUtil.newURI(url).QueryInterface(Ci.nsIFileURL);
+
+      return uri.file.exists();
+    } catch (e) {
+      return false;
+    }
+  }),
+
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupportsWeakReference]),
+
+  observe() {
+    // Clear any module resolution caches when the startup cache is flushed,
+    // since it probably means we're loading new copies of extensions.
+    this.zipContentsCache.clear();
+    this.filesCache.clear();
+  },
+
+  /**
+   * Returns the base URL for the given URL, if one can be determined. For
+   * a resource: URL, this is the root of the resource package. For a jar:
+   * URL, it is the root of the JAR file. Otherwise, null is returned.
+   *
+   * @param {string} url
+   * @returns {string?}
+   */
+  getBaseURL(url) {
+    // By using simple string matching for the common case of resource: URLs
+    // backed by jar: URLs, we can avoid creating any nsIURI objects for the
+    // common case where the JAR contents are already cached.
+    if (url.startsWith("resource://")) {
+      return /^resource:\/\/[^\/]+\//.exec(url)[0];
+    }
+
+    let uri = NetUtil.newURI(url);
+    if (uri instanceof Ci.nsIJARURI) {
+      return `jar:${uri.JARFile.spec}!/`;
+    }
+
+    return null;
+  },
+
+  /**
+   * Returns true if the target of the given URL exists as a local file,
+   * or as an entry in a local zip file.
+   *
+   * @param {string} url
+   * @returns {boolean}
+   */
+  exists(url) {
+    if (!/\.(?:js|json)$/.test(url)) {
+      url = addTrailingSlash(url);
+    }
+
+    let baseURL = this.getBaseURL(url);
+    let scripts = baseURL && this.zipContentsCache.get(baseURL);
+    if (scripts) {
+      return scripts.has(url);
+    }
+
+    return this.filesCache.get(url);
+  },
+}
+addObserver(urlCache, "startupcache-invalidate", true);
+
+function readURI(uri) {
+  let nsURI = NetUtil.newURI(uri);
+  if (nsURI.scheme == "resource") {
+    // Resolve to a real URI, this will catch any obvious bad paths without
+    // logging assertions in debug builds, see bug 1135219
+    uri = resProto.resolveURI(nsURI);
+  }
+
+  let stream = NetUtil.newChannel({
+    uri: NetUtil.newURI(uri, 'UTF-8'),
+    loadUsingSystemPrincipal: true}
+  ).open2();
+  let count = stream.available();
+  let data = NetUtil.readInputStreamToString(stream, count, {
+    charset: 'UTF-8'
+  });
+
+  stream.close();
+
+  return data;
+}
+
+// Combines all arguments into a resolved, normalized path
+function join(base, ...paths) {
+  // If this is an absolute URL, we need to normalize only the path portion,
+  // or we wind up stripping too many slashes and producing invalid URLs.
+  let match = /^((?:resource|file|chrome)\:\/\/[^\/]*|jar:[^!]+!)(.*)/.exec(base);
+  if (match) {
+    return match[1] + normalize(pathJoin(match[2], ...paths));
+  }
+
+  return normalize(pathJoin(base, ...paths));
+}
+Loader.join = join;
+
+// Function takes set of options and returns a JS sandbox. Function may be
+// passed set of options:
+//  - `name`: A string value which identifies the sandbox in about:memory. Will
+//    throw exception if omitted.
+// - `principal`: String URI or `nsIPrincipal` for the sandbox. Defaults to
+//    system principal.
+// - `prototype`: Ancestor for the sandbox that will be created. Defaults to
+//    `{}`.
+// - `wantXrays`: A Boolean value indicating whether code outside the sandbox
+//    wants X-ray vision with respect to objects inside the sandbox. Defaults
+//    to `true`.
+// - `sandbox`: A sandbox to share JS compartment with. If omitted new
+//    compartment will be created.
+// - `metadata`: A metadata object associated with the sandbox. It should
+//    be JSON-serializable.
+// For more details see:
+// https://developer.mozilla.org/en/Components.utils.Sandbox
+const Sandbox = iced(function Sandbox(options) {
+  // Normalize options and rename to match `Cu.Sandbox` expectations.
+  options = {
+    // Do not expose `Components` if you really need them (bad idea!) you
+    // still can expose via prototype.
+    wantComponents: false,
+    sandboxName: options.name,
+    principal: 'principal' in options ? options.principal : systemPrincipal,
+    wantXrays: 'wantXrays' in options ? options.wantXrays : true,
+    wantGlobalProperties: 'wantGlobalProperties' in options ?
+                          options.wantGlobalProperties : [],
+    sandboxPrototype: 'prototype' in options ? options.prototype : {},
+    invisibleToDebugger: 'invisibleToDebugger' in options ?
+                         options.invisibleToDebugger : false,
+    metadata: 'metadata' in options ? options.metadata : {},
+    waiveIntereposition: !!options.waiveIntereposition
+  };
+
+  if (options.metadata && options.metadata.addonID) {
+    options.addonId = options.metadata.addonID;
+  }
+
+  let sandbox = Cu.Sandbox(options.principal, options);
+
+  // Each sandbox at creation gets set of own properties that will be shadowing
+  // ones from it's prototype. We override delete such `sandbox` properties
+  // to avoid shadowing.
+  delete sandbox.Iterator;
+  delete sandbox.Components;
+  delete sandbox.importFunction;
+  delete sandbox.debug;
+
+  return sandbox;
+});
+Loader.Sandbox = Sandbox;
+
+// Evaluates code from the given `uri` into given `sandbox`. If
+// `options.source` is passed, then that code is evaluated instead.
+// Optionally following options may be given:
+// - `options.encoding`: Source encoding, defaults to 'UTF-8'.
+// - `options.line`: Line number to start count from for stack traces.
+//    Defaults to 1.
+// - `options.version`: Version of JS used, defaults to '1.8'.
+const evaluate = iced(function evaluate(sandbox, uri, options) {
+  let { source, line, version, encoding } = override({
+    encoding: 'UTF-8',
+    line: 1,
+    version: '1.8',
+    source: null
+  }, options);
+
+  return source ? Cu.evalInSandbox(source, sandbox, version, uri, line)
+                : loadSubScript(uri, sandbox, encoding);
+});
+Loader.evaluate = evaluate;
+
+// Populates `exports` of the given CommonJS `module` object, in the context
+// of the given `loader` by evaluating code associated with it.
+const load = iced(function load(loader, module) {
+  let { sandboxes, globals, loadModuleHook } = loader;
+  let require = Require(loader, module);
+
+  // We expose set of properties defined by `CommonJS` specification via
+  // prototype of the sandbox. Also globals are deeper in the prototype
+  // chain so that each module has access to them as well.
+  let descriptors = descriptor({
+    require: require,
+    module: module,
+    exports: module.exports,
+    get Components() {
+      // Expose `Components` property to throw error on usage with
+      // additional information
+      throw new ReferenceError(COMPONENT_ERROR);
+    }
+  });
+
+  let sandbox;
+  if ((loader.useSharedGlobalSandbox || isSystemURI(module.uri)) &&
+      loader.sharedGlobalBlocklist.indexOf(module.id) == -1) {
+    // Create a new object in this sandbox, that will be used as
+    // the scope object for this particular module
+    sandbox = new loader.sharedGlobalSandbox.Object();
+    // Inject all expected globals in the scope object
+    getOwnIdentifiers(globals).forEach(function(name) {
+      descriptors[name] = getOwnPropertyDescriptor(globals, name)
+      descriptors[name].configurable = true;
+    });
+    Object.defineProperties(sandbox, descriptors);
+  }
+  else {
+    sandbox = Sandbox({
+      name: module.uri,
+      prototype: Object.create(globals, descriptors),
+      wantXrays: false,
+      wantGlobalProperties: module.id == "sdk/indexed-db" ? ["indexedDB"] : [],
+      invisibleToDebugger: loader.invisibleToDebugger,
+      metadata: {
+        addonID: loader.id,
+        URI: module.uri
+      }
+    });
+  }
+  sandboxes[module.uri] = sandbox;
+
+  try {
+    evaluate(sandbox, module.uri);
+  }
+  catch (error) {
+    let { message, fileName, lineNumber } = error;
+    let stack = error.stack || Error().stack;
+    let frames = parseStack(stack).filter(isntLoaderFrame);
+    let toString = String(error);
+    let file = sourceURI(fileName);
+
+    // Note that `String(error)` where error is from subscript loader does
+    // not puts `:` after `"Error"` unlike regular errors thrown by JS code.
+    // If there is a JS stack then this error has already been handled by an
+    // inner module load.
+    if (/^Error opening input stream/.test(String(error))) {
+      let caller = frames.slice(0).pop();
+      fileName = caller.fileName;
+      lineNumber = caller.lineNumber;
+      message = "Module `" + module.id + "` is not found at " + module.uri;
+      toString = message;
+    }
+    // Workaround for a Bug 910653. Errors thrown by subscript loader
+    // do not include `stack` field and above created error won't have
+    // fileName or lineNumber of the module being loaded, so we ensure
+    // it does.
+    else if (frames[frames.length - 1].fileName !== file) {
+      frames.push({ fileName: file, lineNumber: lineNumber, name: "" });
+    }
+
+    let prototype = typeof(error) === "object" ? error.constructor.prototype :
+                    Error.prototype;
+
+    throw Object.create(prototype, {
+      message: { value: message, writable: true, configurable: true },
+      fileName: { value: fileName, writable: true, configurable: true },
+      lineNumber: { value: lineNumber, writable: true, configurable: true },
+      stack: { value: serializeStack(frames), writable: true, configurable: true },
+      toString: { value: () => toString, writable: true, configurable: true },
+    });
+  }
+
+  if (loadModuleHook) {
+    module = loadModuleHook(module, require);
+  }
+
+  if (loader.checkCompatibility) {
+    let err = XulApp.incompatibility(module);
+    if (err) {
+      throw err;
+    }
+  }
+
+  if (module.exports && typeof(module.exports) === 'object')
+    freeze(module.exports);
+
+  return module;
+});
+Loader.load = load;
+
+// Utility function to normalize module `uri`s so they have `.js` extension.
+function normalizeExt(uri) {
+  return isJSURI(uri) ? uri :
+         isJSONURI(uri) ? uri :
+         isJSMURI(uri) ? uri :
+         uri + '.js';
+}
+
+// Strips `rootURI` from `string` -- used to remove absolute resourceURI
+// from a relative path
+function stripBase(rootURI, string) {
+  return string.replace(rootURI, './');
+}
+
+// Utility function to join paths. In common case `base` is a
+// `requirer.uri` but in some cases it may be `baseURI`. In order to
+// avoid complexity we require `baseURI` with a trailing `/`.
+const resolve = iced(function resolve(id, base) {
+  if (!isRelative(id))
+    return id;
+
+  let baseDir = dirname(base);
+  if (!baseDir)
+    return normalize(id);
+
+  let resolved = join(baseDir, id);
+
+  // Joining and normalizing removes the './' from relative files.
+  // We need to ensure the resolution still has the root
+  if (isRelative(base))
+    resolved = './' + resolved;
+
+  return resolved;
+});
+Loader.resolve = resolve;
+
+// Attempts to load `path` and then `path.js`
+// Returns `path` with valid file, or `undefined` otherwise
+function resolveAsFile(path) {
+  // Append '.js' to path name unless it's another support filetype
+  path = normalizeExt(path);
+  if (urlCache.exists(path)) {
+    return path;
+  }
+
+  return null;
+}
+
+// Attempts to load `path/package.json`'s `main` entry,
+// followed by `path/index.js`, or `undefined` otherwise
+function resolveAsDirectory(path) {
+  try {
+    // If `path/package.json` exists, parse the `main` entry
+    // and attempt to load that
+    let manifestPath = addTrailingSlash(path) + 'package.json';
+
+    let main = (urlCache.exists(manifestPath) &&
+                getManifestMain(JSON.parse(readURI(manifestPath))));
+    if (main) {
+      let found = resolveAsFile(join(path, main));
+      if (found) {
+        return found
+      }
+    }
+  } catch (e) {}
+
+  return resolveAsFile(addTrailingSlash(path) + 'index.js');
+}
+
+function resolveRelative(rootURI, modulesDir, id) {
+  let fullId = join(rootURI, modulesDir, id);
+
+  let resolvedPath = (resolveAsFile(fullId) ||
+                      resolveAsDirectory(fullId));
+  if (resolvedPath) {
+    return stripBase(rootURI, resolvedPath);
+  }
+
+  return null;
+}
+
+// From `resolve` module
+// https://github.com/substack/node-resolve/blob/master/lib/node-modules-paths.js
+function* getNodeModulePaths(rootURI, start) {
+  let moduleDir = 'node_modules';
+
+  let parts = start.split('/');
+  while (parts.length) {
+    let leaf = parts.pop();
+    let path = join(...parts, leaf, moduleDir);
+    if (leaf !== moduleDir && urlCache.exists(join(rootURI, path))) {
+      yield path;
+    }
+  }
+
+  if (urlCache.exists(join(rootURI, moduleDir))) {
+    yield moduleDir;
+  }
+}
+
+// Node-style module lookup
+// Takes an id and path and attempts to load a file using node's resolving
+// algorithm.
+// `id` should already be resolved relatively at this point.
+// http://nodejs.org/api/modules.html#modules_all_together
+const nodeResolve = iced(function nodeResolve(id, requirer, { rootURI }) {
+  // Resolve again
+  id = Loader.resolve(id, requirer);
+
+  // If this is already an absolute URI then there is no resolution to do
+  if (isAbsoluteURI(id)) {
+    return null;
+  }
+
+  // we assume that extensions are correct, i.e., a directory doesnt't have '.js'
+  // and a js file isn't named 'file.json.js'
+  let resolvedPath;
+
+  if ((resolvedPath = resolveRelative(rootURI, "", id))) {
+    return resolvedPath;
+  }
+
+  // If the requirer is an absolute URI then the node module resolution below
+  // won't work correctly as we prefix everything with rootURI
+  if (isAbsoluteURI(requirer)) {
+    return null;
+  }
+
+  // If manifest has dependencies, attempt to look up node modules
+  // in the `dependencies` list
+  for (let modulesDir of getNodeModulePaths(rootURI, dirname(requirer))) {
+    if ((resolvedPath = resolveRelative(rootURI, modulesDir, id))) {
+      return resolvedPath;
+    }
+  }
+
+  // We would not find lookup for things like `sdk/tabs`, as that's part of
+  // the alias mapping. If during `generateMap`, the runtime lookup resolves
+  // with `resolveURI` -- if during runtime, then `resolve` will throw.
+  return null;
+});
+
+Loader.nodeResolve = nodeResolve;
+
+function addTrailingSlash(path) {
+  return path.replace(/\/*$/, "/");
+}
+
+const resolveURI = iced(function resolveURI(id, mapping) {
+  // Do not resolve if already a resource URI
+  if (isAbsoluteURI(id))
+    return normalizeExt(id);
+
+  for (let [path, uri] of mapping) {
+    // Strip off any trailing slashes to make comparisons simpler
+    let stripped = path.replace(/\/+$/, "");
+
+    // We only want to match path segments explicitly. Examples:
+    // * "foo/bar" matches for "foo/bar"
+    // * "foo/bar" matches for "foo/bar/baz"
+    // * "foo/bar" does not match for "foo/bar-1"
+    // * "foo/bar/" does not match for "foo/bar"
+    // * "foo/bar/" matches for "foo/bar/baz"
+    //
+    // Check for an empty path, an exact match, or a substring match
+    // with the next character being a forward slash.
+    if(stripped === "" || id === stripped || id.startsWith(stripped + "/")) {
+      return normalizeExt(id.replace(path, uri));
+    }
+  }
+  return null;
+});
+Loader.resolveURI = resolveURI;
+
+// Creates version of `require` that will be exposed to the given `module`
+// in the context of the given `loader`. Each module gets own limited copy
+// of `require` that is allowed to load only a modules that are associated
+// with it during link time.
+const Require = iced(function Require(loader, requirer) {
+  let {
+    modules, mapping, resolve: loaderResolve, load,
+    manifest, rootURI, isNative, requireMap,
+    requireHook
+  } = loader;
+
+  if (isSystemURI(requirer.uri)) {
+    // Built-in modules don't require the expensive module resolution
+    // algorithm used by SDK add-ons, so give them the more efficient standard
+    // resolve instead.
+    isNative = false;
+    loaderResolve = Loader.resolve;
+  }
+
+  function require(id) {
+    if (!id) // Throw if `id` is not passed.
+      throw Error('You must provide a module name when calling require() from '
+                  + requirer.id, requirer.uri);
+
+    if (requireHook) {
+      return requireHook(id, _require);
+    }
+
+    return _require(id);
+  }
+
+  function _require(id) {
+    let { uri, requirement } = getRequirements(id);
+    let module = null;
+    // If module is already cached by loader then just use it.
+    if (uri in modules) {
+      module = modules[uri];
+    }
+    else if (isJSMURI(uri)) {
+      module = modules[uri] = Module(requirement, uri);
+      module.exports = Cu.import(uri, {});
+      freeze(module);
+    }
+    else if (isJSONURI(uri)) {
+      let data;
+
+      // First attempt to load and parse json uri
+      // ex: `test.json`
+      // If that doesn't exist, check for `test.json.js`
+      // for node parity
+      try {
+        data = JSON.parse(readURI(uri));
+        module = modules[uri] = Module(requirement, uri);
+        module.exports = data;
+        freeze(module);
+      }
+      catch (err) {
+        // If error thrown from JSON parsing, throw that, do not
+        // attempt to find .json.js file
+        if (err && /JSON\.parse/.test(err.message))
+          throw err;
+        uri = uri + '.js';
+      }
+    }
+
+    // If not yet cached, load and cache it.
+    // We also freeze module to prevent it from further changes
+    // at runtime.
+    if (!(uri in modules)) {
+      // Many of the loader's functionalities are dependent
+      // on modules[uri] being set before loading, so we set it and
+      // remove it if we have any errors.
+      module = modules[uri] = Module(requirement, uri);
+      try {
+        freeze(load(loader, module));
+      }
+      catch (e) {
+        // Clear out modules cache so we can throw on a second invalid require
+        delete modules[uri];
+        // Also clear out the Sandbox that was created
+        delete loader.sandboxes[uri];
+        throw e;
+      }
+    }
+
+    return module.exports;
+  }
+
+  // Resolution function taking a module name/path and
+  // returning a resourceURI and a `requirement` used by the loader.
+  // Used by both `require` and `require.resolve`.
+  function getRequirements(id) {
+    if (!id) // Throw if `id` is not passed.
+      throw Error('you must provide a module name when calling require() from '
+                  + requirer.id, requirer.uri);
+
+    let requirement, uri;
+
+    // TODO should get native Firefox modules before doing node-style lookups
+    // to save on loading time
+    if (isNative) {
+      // If a requireMap is available from `generateMap`, use that to
+      // immediately resolve the node-style mapping.
+      // TODO: write more tests for this use case
+      if (requireMap && requireMap[requirer.id])
+        requirement = requireMap[requirer.id][id];
+
+      let { overrides } = manifest.jetpack;
+      for (let key in overrides) {
+        // ignore any overrides using relative keys
+        if (/^[.\/]/.test(key)) {
+          continue;
+        }
+
+        // If the override is for x -> y,
+        // then using require("x/lib/z") to get reqire("y/lib/z")
+        // should also work
+        if (id == key || id.startsWith(key + "/")) {
+          id = overrides[key] + id.substr(key.length);
+          id = id.replace(/^[.\/]+/, "");
+        }
+      }
+
+      // For native modules, we want to check if it's a module specified
+      // in 'modules', like `chrome`, or `@loader` -- if it exists,
+      // just set the uri to skip resolution
+      if (!requirement && modules[id])
+        uri = requirement = id;
+
+      // If no requireMap was provided, or resolution not found in
+      // the requireMap, and not a npm dependency, attempt a runtime lookup
+      if (!requirement && !NODE_MODULES.has(id)) {
+        // If `isNative` defined, this is using the new, native-style
+        // loader, not cuddlefish, so lets resolve using node's algorithm
+        // and get back a path that needs to be resolved via paths mapping
+        // in `resolveURI`
+        requirement = loaderResolve(id, requirer.id, {
+          manifest: manifest,
+          rootURI: rootURI
+        });
+      }
+
+      // If not found in the map, not a node module, and wasn't able to be
+      // looked up, it's something
+      // found in the paths most likely, like `sdk/tabs`, which should
+      // be resolved relatively if needed using traditional resolve
+      if (!requirement) {
+        requirement = isRelative(id) ? Loader.resolve(id, requirer.id) : id;
+      }
+    }
+    else if (modules[id]) {
+      uri = requirement = id;
+    }
+    else if (requirer) {
+      // Resolve `id` to its requirer if it's relative.
+      requirement = loaderResolve(id, requirer.id);
+    }
+    else {
+      requirement = id;
+    }
+
+    // Resolves `uri` of module using loaders resolve function.
+    uri = uri || resolveURI(requirement, mapping);
+
+    // Throw if `uri` can not be resolved.
+    if (!uri) {
+      throw Error('Module: Can not resolve "' + id + '" module required by ' +
+                  requirer.id + ' located at ' + requirer.uri, requirer.uri);
+    }
+
+    return { uri: uri, requirement: requirement };
+  }
+
+  // Expose the `resolve` function for this `Require` instance
+  require.resolve = _require.resolve = function resolve(id) {
+    let { uri } = getRequirements(id);
+    return uri;
+  }
+
+  // This is like webpack's require.context.  It returns a new require
+  // function that prepends the prefix to any requests.
+  require.context = prefix => {
+    return id => {
+      return require(prefix + id);
+    };
+  };
+
+  // Make `require.main === module` evaluate to true in main module scope.
+  require.main = loader.main === requirer ? requirer : undefined;
+  return iced(require);
+});
+Loader.Require = Require;
+
+const main = iced(function main(loader, id) {
+  // If no main entry provided, and native loader is used,
+  // read the entry in the manifest
+  if (!id && loader.isNative)
+    id = getManifestMain(loader.manifest);
+  let uri = resolveURI(id, loader.mapping);
+  let module = loader.main = loader.modules[uri] = Module(id, uri);
+  return loader.load(loader, module).exports;
+});
+Loader.main = main;
+
+// Makes module object that is made available to CommonJS modules when they
+// are evaluated, along with `exports` and `require`.
+const Module = iced(function Module(id, uri) {
+  return Object.create(null, {
+    id: { enumerable: true, value: id },
+    exports: { enumerable: true, writable: true, value: Object.create(null),
+               configurable: true },
+    uri: { value: uri }
+  });
+});
+Loader.Module = Module;
+
+// Takes `loader`, and unload `reason` string and notifies all observers that
+// they should cleanup after them-self.
+const unload = iced(function unload(loader, reason) {
+  // subject is a unique object created per loader instance.
+  // This allows any code to cleanup on loader unload regardless of how
+  // it was loaded. To handle unload for specific loader subject may be
+  // asserted against loader.destructor or require('@loader/unload')
+  // Note: We don not destroy loader's module cache or sandboxes map as
+  // some modules may do cleanup in subsequent turns of event loop. Destroying
+  // cache may cause module identity problems in such cases.
+  let subject = { wrappedJSObject: loader.destructor };
+  notifyObservers(subject, 'sdk:loader:destroy', reason);
+});
+Loader.unload = unload;
+
+// Function makes new loader that can be used to load CommonJS modules
+// described by a given `options.manifest`. Loader takes following options:
+// - `globals`: Optional map of globals, that all module scopes will inherit
+//   from. Map is also exposed under `globals` property of the returned loader
+//   so it can be extended further later. Defaults to `{}`.
+// - `modules` Optional map of built-in module exports mapped by module id.
+//   These modules will incorporated into module cache. Each module will be
+//   frozen.
+// - `resolve` Optional module `id` resolution function. If given it will be
+//   used to resolve module URIs, by calling it with require term, requirer
+//   module object (that has `uri` property) and `baseURI` of the loader.
+//   If `resolve` does not returns `uri` string exception will be thrown by
+//   an associated `require` call.
+function Loader(options) {
+  if (options.sharedGlobalBlacklist && !options.sharedGlobalBlocklist) {
+    options.sharedGlobalBlocklist = options.sharedGlobalBlacklist;
+  }
+  let {
+    modules, globals, resolve, paths, rootURI, manifest, requireMap, isNative,
+    metadata, sharedGlobal, sharedGlobalBlocklist, checkCompatibility, waiveIntereposition
+  } = override({
+    paths: {},
+    modules: {},
+    globals: {
+      get console() {
+        // Import Console.jsm from here to prevent loading it until someone uses it
+        let { ConsoleAPI } = Cu.import("resource://gre/modules/Console.jsm");
+        let console = new ConsoleAPI({
+          consoleID: options.id ? "addon/" + options.id : ""
+        });
+        Object.defineProperty(this, "console", { value: console });
+        return this.console;
+      }
+    },
+    checkCompatibility: false,
+    resolve: options.isNative ?
+      // Make the returned resolve function have the same signature
+      (id, requirer) => Loader.nodeResolve(id, requirer, { rootURI: rootURI }) :
+      Loader.resolve,
+    sharedGlobalBlocklist: ["sdk/indexed-db"],
+    waiveIntereposition: false
+  }, options);
+
+  // Create overrides defaults, none at the moment
+  if (typeof manifest != "object" || !manifest) {
+    manifest = {};
+  }
+  if (typeof manifest.jetpack != "object" || !manifest.jetpack) {
+    manifest.jetpack = {
+      overrides: {}
+    };
+  }
+  if (typeof manifest.jetpack.overrides != "object" || !manifest.jetpack.overrides) {
+    manifest.jetpack.overrides = {};
+  }
+
+  // We create an identity object that will be dispatched on an unload
+  // event as subject. This way unload listeners will be able to assert
+  // which loader is unloaded. Please note that we intentionally don't
+  // use `loader` as subject to prevent a loader access leakage through
+  // observer notifications.
+  let destructor = freeze(Object.create(null));
+
+  // Make mapping array that is sorted from longest path to shortest path.
+  let mapping = Object.keys(paths)
+                      .sort((a, b) => b.length - a.length)
+                      .map(path => [path, paths[path]]);
+
+  // Define pseudo modules.
+  modules = override({
+    '@loader/unload': destructor,
+    '@loader/options': options,
+    'chrome': { Cc: Cc, Ci: Ci, Cu: Cu, Cr: Cr, Cm: Cm,
+                CC: bind(CC, Components), components: Components,
+                // `ChromeWorker` has to be inject in loader global scope.
+                // It is done by bootstrap.js:loadSandbox for the SDK.
+                ChromeWorker: ChromeWorker
+    }
+  }, modules);
+
+  const builtinModuleExports = modules;
+  modules = {};
+  for (let id of Object.keys(builtinModuleExports)) {
+    // We resolve `uri` from `id` since modules are cached by `uri`.
+    let uri = resolveURI(id, mapping);
+    // In native loader, the mapping will not contain values for
+    // pseudomodules -- store them as their ID rather than the URI
+    if (isNative && !uri)
+      uri = id;
+    let module = Module(id, uri);
+
+    // Lazily expose built-in modules in order to
+    // allow them to be loaded lazily.
+    Object.defineProperty(module, "exports", {
+      enumerable: true,
+      get: function() {
+        return builtinModuleExports[id];
+      }
+    });
+
+    modules[uri] = freeze(module);
+  }
+
+  // Create the unique sandbox we will be using for all modules,
+  // so that we prevent creating a new comportment per module.
+  // The side effect is that all modules will share the same
+  // global objects.
+  let sharedGlobalSandbox = Sandbox({
+    name: "Addon-SDK",
+    wantXrays: false,
+    wantGlobalProperties: [],
+    invisibleToDebugger: options.invisibleToDebugger || false,
+    metadata: {
+      addonID: options.id,
+      URI: "Addon-SDK"
+    },
+    prototype: options.sandboxPrototype || {}
+  });
+
+  // Loader object is just a representation of a environment
+  // state. We freeze it and mark make it's properties non-enumerable
+  // as they are pure implementation detail that no one should rely upon.
+  let returnObj = {
+    destructor: { enumerable: false, value: destructor },
+    globals: { enumerable: false, value: globals },
+    mapping: { enumerable: false, value: mapping },
+    // Map of module objects indexed by module URIs.
+    modules: { enumerable: false, value: modules },
+    metadata: { enumerable: false, value: metadata },
+    useSharedGlobalSandbox: { enumerable: false, value: !!sharedGlobal },
+    sharedGlobalSandbox: { enumerable: false, value: sharedGlobalSandbox },
+    sharedGlobalBlocklist: { enumerable: false, value: sharedGlobalBlocklist },
+    sharedGlobalBlacklist: { enumerable: false, value: sharedGlobalBlocklist },
+    // Map of module sandboxes indexed by module URIs.
+    sandboxes: { enumerable: false, value: {} },
+    resolve: { enumerable: false, value: resolve },
+    // ID of the addon, if provided.
+    id: { enumerable: false, value: options.id },
+    // Whether the modules loaded should be ignored by the debugger
+    invisibleToDebugger: { enumerable: false,
+                           value: options.invisibleToDebugger || false },
+    load: { enumerable: false, value: options.load || load },
+    checkCompatibility: { enumerable: false, value: checkCompatibility },
+    requireHook: { enumerable: false, value: options.requireHook },
+    loadModuleHook: { enumerable: false, value: options.loadModuleHook },
+    // Main (entry point) module, it can be set only once, since loader
+    // instance can have only one main module.
+    main: new function() {
+      let main;
+      return {
+        enumerable: false,
+        get: function() { return main; },
+        // Only set main if it has not being set yet!
+        set: function(module) { main = main || module; }
+      }
+    }
+  };
+
+  if (isNative) {
+    returnObj.isNative = { enumerable: false, value: true };
+    returnObj.manifest = { enumerable: false, value: manifest };
+    returnObj.requireMap = { enumerable: false, value: requireMap };
+    returnObj.rootURI = { enumerable: false, value: addTrailingSlash(rootURI) };
+  }
+
+  return freeze(Object.create(null, returnObj));
+};
+Loader.Loader = Loader;
+
+var isSystemURI = uri => /^resource:\/\/(gre|devtools|testing-common)\//.test(uri);
+
+var isJSONURI = uri => uri.endsWith('.json');
+var isJSMURI = uri => uri.endsWith('.jsm');
+var isJSURI = uri => uri.endsWith('.js');
+var isAbsoluteURI = uri => uri.startsWith("resource://") ||
+                           uri.startsWith("chrome://") ||
+                           uri.startsWith("file://");
+var isRelative = id => id.startsWith(".");
+
+// Default `main` entry to './index.js' and ensure is relative,
+// since node allows 'lib/index.js' without relative `./`
+function getManifestMain(manifest) {
+  let main = manifest.main || './index.js';
+  return isRelative(main) ? main : './' + main;
+}
+
+module.exports = iced(Loader);
+});